Kant's Theory of Knowledge, by Harold Arthur 1 Kant's Theory of Knowledge, by Harold Arthur The Project Gutenberg ebook, Kant's Theory of Knowledge, by Harold Arthur Prichard This ebook is for the use of anyone anywhere at no cost and with almost no restrictions whatsoever. You may copy it, give it away or re-use it under the terms of the Project Gutenberg License included with this ebook or online at www.gutenberg.org Title: Kant's Theory of Knowledge Author: Harold Arthur Prichard Release Date: June 5, 2010 [ebook #32701] Language: English Character set encoding: ISO-8859-1 ***START OF THE PROJECT GUTENBERG EBOOK KANT'S THEORY OF KNOWLEDGE*** E-text prepared by Meredith Bach, lizardcry, and the Project Gutenberg Online Distributed Proofreading Team (http://www.pgdp.net) from page images generously made available by Internet Archive/Canadian Libraries (http://www.archive.org/details/toronto) Note: Images of the original pages are available through Internet Archive/Canadian Libraries. See http://www.archive.org/details/kantknowledge00pricuoft
Kant's Theory of Knowledge, by Harold Arthur 2 Transcriber's note: 1. Text in italics is enclosed by underscores (italics). 2. The original text includes Greek characters. For this text version these letters have been replaced with transliterations represented within square brackets [Greek: ]. Also greek letters alpha and beta are represented as [alpha] and [beta] in this text. 3. A subscript is indicated by an underscore followed by the subscript in curly braces. For example, a{2} indicates a with subscript 2. 4. Footnotes have been moved to the end of the paragraph wherein they have been referred to. 5. Other than the corrections listed above, printer's inconsistencies in spelling, punctuation and hyphenation have been retained. KANT'S THEORY OF KNOWLEDGE by H. A. PRICHARD Fellow of Trinity College, Oxford Oxford At the Clarendon Press 1909 Henry Frowde, M.A. Publisher to the University of Oxford London, Edinburgh, New York Toronto and Melbourne PREFACE This book is an attempt to think out the nature and tenability of Kant's Transcendental Idealism, an attempt animated by the conviction that even the elucidation of Kant's meaning, apart from any criticism, is impossible without a discussion on their own merits of the main issues which he raises. My obligations are many and great: to Caird's Critical Philosophy of Kant and to the translations of Meiklejohn, Max Müller, and Professor Mahaffy; to Mr. J. A. Smith, Fellow of Balliol College, and to Mr. H. W. B. Joseph, Fellow of New College, for what I have learned from them in discussion; to Mr. A. J. Jenkinson, Fellow of Brasenose College, for reading and commenting on the first half of the MS.; to Mr. H. H. Joachim, Fellow of Merton College, for making many important suggestions, especially with regard to matters of translation; to Mr. Joseph, for reading the whole of the proofs and for making many valuable corrections; and, above all, to my wife for constant and unfailing help throughout, and to Professor Cook Wilson, to have been whose pupil I count the greatest of philosophical good fortunes. Some years ago it was my privilege to be a member of a class with which Professor Cook Wilson read a portion of Kant's Critique of Pure Reason, and subsequently I have had the advantage of discussing with him several of the more important passages. I am especially indebted to him in my discussion of the following topics: the distinction between the Sensibility and the Understanding (pp. 27-31, 146-9, 162-6), the term 'form of perception' (pp. 37, 40, 133 fin.-135), the Metaphysical Exposition of Space (pp. 41-8), Inner Sense (Ch. V, and pp. 138-9), the Metaphysical Deduction of the Categories (pp. 149-53), Kant's account of 'the reference of representations to an object' (pp. 178-86), an implication of perspective (p. 90), the impossibility of a 'theory' of knowledge (p. 245), and the points considered, pp. 200 med.-202 med., 214 med.-215 med., and 218. The views expressed in the pages referred to originated from Professor Cook Wilson, though it must not be assumed that he would accept them in the form
Kant's Theory of Knowledge, by Harold Arthur 3 in which they are there stated. CONTENTS
CHAPTER I 4 CHAPTER I PAGE THE PROBLEM OF THE Critique 1
CHAPTER II 5 CHAPTER II THE SENSIBILITY AND THE UNDERSTANDING 27
CHAPTER III 6 CHAPTER III SPACE 36
CHAPTER IV 7 CHAPTER IV PHENOMENA AND THINGS IN THEMSELVES 71 NOTE THE FIRST ANTINOMY 101
CHAPTER V 8 CHAPTER V TIME AND INNER SENSE 103
CHAPTER VI 9 CHAPTER VI KNOWLEDGE AND REALITY 115
CHAPTER VII 10 CHAPTER VII THE METAPHYSICAL DEDUCTION OF THE CATEGORIES 140
CHAPTER VIII 11 CHAPTER VIII THE TRANSCENDENTAL DEDUCTION OF THE CATEGORIES 161
CHAPTER IX 12 CHAPTER IX GENERAL CRITICISM OF THE TRANSCENDENTAL DEDUCTION OF THE CATEGORIES 214
CHAPTER X 13 CHAPTER X THE SCHEMATISM OF THE CATEGORIES 246
CHAPTER XI 14 CHAPTER XI THE MATHEMATICAL PRINCIPLES 260
CHAPTER XII 15 CHAPTER XII THE ANALOGIES OF EXPERIENCE 268
CHAPTER XIII 16 CHAPTER XIII THE POSTULATES OF EMPIRICAL THOUGHT 308 NOTE THE REFUTATION OF IDEALISM 319 REFERENCES A = First edition of the Critique of Pure Reason. B = Second edition of the Critique of Pure Reason. Prol. = Kant's Prolegomena to any future Metaphysic. M = Meiklejohn's Translation of the Critique of Pure Reason. Mah. = Mahaffy. Translation of Kant's Prolegomena to any future Metaphysic. (The pages referred to are those of the first edition; these are also to be found in the text of the second edition.) Caird = Caird's Critical Philosophy of Kant.
CHAPTER I 17 CHAPTER I THE PROBLEM OF THE CRITIQUE The problem of the Critique may be stated in outline and approximately in Kant's own words as follows. Human reason is called upon to consider certain questions, which it cannot decline, as they are presented by its own nature, but which it cannot answer. These questions relate to God, freedom of the will, and immortality. And the name for the subject which has to deal with these questions is metaphysics. At one time metaphysics was regarded as the queen of all the sciences, and the importance of its aim justified the title. At first the subject, propounding as it did a dogmatic system, exercised a despotic sway. But its subsequent failure brought it into disrepute. It has constantly been compelled to retrace its steps; there has been fundamental disagreement among philosophers, and no philosopher has successfully refuted his critics. Consequently the current attitude to the subject is one of weariness and indifference. Yet humanity cannot really be indifferent to such problems; even those who profess indifference inevitably make metaphysical assertions; and the current attitude is a sign not of levity but of a refusal to put up with the illusory knowledge offered by contemporary philosophy. Now the objects of metaphysics, God, freedom, and immortality, are not objects of experience in the sense in which a tree or a stone is an object of experience. Hence our views about them cannot be due to experience; they must somehow be apprehended by pure reason, i. e. by thinking and without appeal to experience. Moreover, it is in fact by thinking that men have always tried to solve the problems concerning God, freedom, and immortality. What, then, is the cause of the unsatisfactory treatment of these problems and men's consequent indifference? It must, in some way, lie in a failure to attain the sure scientific method, and really consists in the neglect of an inquiry which should be a preliminary to all others in metaphysics. Men ought to have begun with a critical investigation of pure reason itself. Reason should have examined its own nature, to ascertain in general the extent to which it is capable of attaining knowledge without the aid of experience. This examination will decide whether reason is able to deal with the problems of God, freedom, and immortality at all; and without it no discussion of these problems will have a solid foundation. It is this preliminary investigation which the Critique of Pure Reason proposes to undertake. Its aim is to answer the question, 'How far can reason go, without the material presented and the aid furnished by experience?' and the result furnishes the solution, or at least the key to the solution, of all metaphysical problems. Kant's problem, then, is similar to Locke's. Locke states[1] that his purpose is to inquire into the original, certainty, and extent of human knowledge; and he says, "If, by this inquiry into the nature of the understanding I can discover the powers thereof; how far they reach, to what things they are in any degree proportionate, and where they fail us; I suppose it may be of use to prevail with the busy mind of man, to be more cautious in meddling with things exceeding its comprehension; to stop when it is at the utmost extent of its tether; and to sit down in a quiet ignorance of those things, which, upon examination, are found to be beyond the reach of our capacities." Thus, to use Dr. Caird's analogy,[2] the task which both Locke and Kant set themselves resembled that of investigating a telescope, before turning it upon the stars, to determine its competence for the work. [1] Locke's Essay, i, 1, 2, 4. [2] Caird, i, 10. The above outline of Kant's problem is of course only an outline. Its definite formulation is expressed in the well-known question, 'How are a priori synthetic judgements possible?'[3] To determine the meaning of this question it is necessary to begin with some consideration of the terms 'a priori' and 'synthetic'. [3] B. 19, M. 12.
CHAPTER I 18 While there is no difficulty in determining what Kant would have recognized as an a priori judgement, there is difficulty in determining what he meant by calling such a judgement a priori. The general account is given in the first two sections of the Introduction. An a priori judgement is introduced as something opposed to an a posteriori judgement, or a judgement which has its source in experience. Instances of the latter would be 'This body is heavy', and 'This body is hot'. The point of the word 'experience' is that there is direct apprehension of some individual, e. g. an individual body. To say that a judgement has its source in experience is of course to imply a distinction between the judgement and experience, and the word 'source' may be taken to mean that the judgement depends for its validity upon the experience of the individual thing to which the judgement relates. An a priorijudgement, then, as first described, is simply a judgement which is not a posteriori. It is independent of all experience; in other words, its validity does not depend on the experience of individual things. It might be illustrated by the judgement that all three-sided figures must have three angles. So far, then, no positive meaning has been given to a priori.[4] [4] Kant is careful to exclude from the class of a priori judgements proper what may be called relatively a priori judgements, viz. judgements which, though not independent of all experience, are independent of experience of the facts to which they relate. "Thus one would say of a man who undermined the foundations of his house that he might have known a priori that it would fall down, i. e. that he did not need to wait for the experience of its actual falling down. But still he could not know this wholly a priori, for he had first to learn through experience that bodies are heavy and consequently fall, if their supports are taken away." (B. 2, M. 2.) Kant then proceeds, not as we should expect, to state the positive meaning of a priori; but to give tests for what is a priori. Since a test implies a distinction between itself and what is tested, it is implied that the meaning of a priori is already known.[5] [5] It may be noted that in this passage (Introduction, 1 and 2) Kant is inconsistent in his use of the term 'pure'. Pure knowledge is introduced as a species of a priori knowledge: "A priori knowledge, if nothing empirical is mixed with it, is called pure". (B. 3, M. 2, 17.) And in accordance with this, the proposition 'every change has a cause' is said to be a priori but impure, because the conception of change can only be derived from experience. Yet immediately afterwards, pure, being opposed in general to empirical, can only mean a priori. Again, in the phrase 'pure a priori' (B. 4 fin., M. 3 med.), the context shows that 'pure' adds nothing to 'a priori', and the proposition 'every change must have a cause' is expressly given as an instance of pure a priori knowledge. The inconsistency of this treatment of the causal rule is explained by the fact that in the former passage he is thinking of the conception of change as empirical, while in the latter he is thinking of the judgement as not empirical. At bottom in this passage 'pure' simply means a priori. The tests given are necessity and strict universality.[6] Since judgements which are necessary and strictly universal cannot be based on experience, their existence is said to indicate another source of knowledge. And Kant gives as illustrations, (1) any proposition in mathematics, and (2) the proposition 'Every change must have a cause'. [6] In reality, these tests come to the same thing, for necessity means the necessity of connexion between the subject and predicate of a judgement, and since empirical universality, to which strict universality is opposed, means numerical universality, as illustrated by the proposition 'All bodies are heavy', the only meaning left for strict universality is that of a universality reached not through an enumeration of instances, but through the apprehension of a necessity of connexion. So far Kant has said nothing which determines the positive meaning of a priori. A clue is, however, to be found in two subsequent phrases. He says that we may content ourselves with having established as a fact the pure use of our faculty of knowledge.[7] And he adds that not only in judgements, but even in conceptions, is an a priori origin manifest.[8] The second statement seems to make the a prioricharacter of a judgement consist in its origin. As this origin cannot be experience, it must, as the first statement implies, lie in our
CHAPTER I 19 faculty of knowledge. Kant's point is that the existence of universal and necessary judgements shows that we must possess a faculty of knowledge capable of yielding knowledge without appeal to experience. The term a priori, then, has some reference to the existence of this faculty; in other words, it gives expression to a doctrine of 'innate ideas'. Perhaps, however, it is hardly fair to press the phrase 'test of a priori judgements'. If so, it may be said that on the whole, by a priori judgements Kant really means judgements which are universal and necessary, and that he regards them as implying a faculty which gives us knowledge without appeal to experience. [7] B. 5, M. 4. [8] Ibid. We may now turn to the term 'synthetic judgement'. Kant distinguishes analytic and synthetic judgements thus. In any judgement the predicate B either belongs to the subject A, as something contained (though covertly) in the conception A, or lies completely outside the conception A, although it stands in relation to it. In the former case the judgement is called analytic, in the latter synthetic.[9] 'All bodies are extended' is an analytic judgement; 'All bodies are heavy' is synthetic. It immediately follows that only synthetic judgements extend our knowledge; for in making an analytic judgement we are only clearing up our conception of the subject. This process yields no new knowledge, for it only gives us a clearer view of what we know already. Further, all judgements based on experience are synthetic, for it would be absurd to base an analytical judgement on experience, when to make the judgement we need not go beyond our own conceptions. On the other hand, a priori judgements are sometimes analytic and sometimes synthetic. For, besides analytical judgements, all judgements in mathematics and certain judgements which underlie physics are asserted independently of experience, and they are synthetic. [9] B. 10, M. 7. Here Kant is obviously right in vindicating the synthetic character of mathematical judgements. In the arithmetical judgement 7 + 5 = 12, the thought of certain units as a group of twelve is no mere repetition of the thought of them as a group of five added to a group of seven. Though the same units are referred to, they are regarded differently. Thus the thought of them as twelve means either that we think of them as formed by adding one unit to a group of eleven, or that we think of them as formed by adding two units to a group of ten, and so on. And the assertion is that the same units, which can be grouped in one way, can also be grouped in another. Similarly, Kant is right in pointing out that the geometrical judgement, 'A straight line between two points is the shortest,' is synthetic, on the ground that the conception of straightness is purely qualitative,[10] while the conception of shortest distance implies the thought of quantity. [10] Straightness means identity of direction. It should now be an easy matter to understand the problem expressed by the question, 'How are a priori synthetic judgements possible?' Its substance may be stated thus. The existence of a posteriorisynthetic judgements presents no difficulty. For experience is equivalent to perception, and, as we suppose, in perception we are confronted with reality, and apprehend it as it is. If I am asked, 'How do I know that my pen is black or my chair hard?' I answer that it is because I see or feel it to be so. In such cases, then, when my assertion is challenged, I appeal to my experience or perception of the reality to which the assertion relates. My appeal raises no difficulty because it conforms to the universal belief that if judgements are to rank as knowledge, they must be made to conform to the nature of things, and that the conformity is established by appeal to actual experience of the things. But do a priori synthetic judgements satisfy this condition? Apparently not. For when I assert that every straight line is the shortest way between its extremities, I have not had, and never can have, experience of all possible straight lines. How then can I be sure that all cases will conform to my judgement? In fact, how can I anticipate my experience at all? How can I make an assertion about any individual until I have had actual experience of it? In an a priori synthetic judgement the
CHAPTER I 20 mind in some way, in virtue of its own powers and independently of experience, makes an assertion to which it claims that reality must conform. Yet why should reality conform? A priori judgements of the other kind, viz. analytic judgements, offer no difficulty, since they are at bottom tautologies, and consequently denial of them is self-contradictory and meaningless. But there is difficulty where a judgement asserts that a term B is connected with another term A, B being neither identical with nor a part of A. In this case there is no contradiction in asserting that A is not B, and it would seem that only experience can determine whether all A is or is not B. Otherwise we are presupposing that things must conform to our ideas about them. Now metaphysics claims to make a priori synthetic judgements, for it does not base its results on any appeal to experience. Hence, before we enter upon metaphysics, we really ought to investigate our right to make a priori synthetic judgements at all. Therein, in fact, lies the importance to metaphysics of the existence of such judgements in mathematics and physics. For it shows that the difficulty is not peculiar to metaphysics, but is a general one shared by other subjects; and the existence of such judgements in mathematics is specially important because there their validity or certainty has never been questioned.[11] The success of mathematics shows that at any rate under certain conditions a priori synthetic judgements are valid, and if we can determine these conditions, we shall be able to decide whether such judgements are possible in metaphysics. In this way we shall be able to settle a disputed case of their validity by examination of an undisputed case. The general problem, however, is simply to show what it is which makes a priori synthetic judgements as such possible; and there will be three cases, those of mathematics, of physics, and of metaphysics. [11] Kant points out that this certainty has usually been attributed to the analytic character of mathematical judgements, and it is of course vital to his argument that he should be successful in showing that they are really synthetic. The outline of the solution of this problem is contained in the Preface to the Second Edition. There Kant urges that the key is to be found by consideration of mathematics and physics. If the question be raised as to what it is that has enabled these subjects to advance, in both cases the answer will be found to lie in a change of method. "Since the earliest times to which the history of human reason reaches, mathematics has, among that wonderful nation the Greeks, followed the safe road of a science. Still it is not to be supposed that it was as easy for this science to strike into, or rather to construct for itself, that royal road, as it was for logic, in which reason has only to do with itself. On the contrary, I believe that it must have remained long in the stage of groping (chiefly among the Egyptians), and that this change is to be ascribed to a revolution, due to the happy thought of one man, through whose experiment the path to be followed was rendered unmistakable for future generations, and the certain way of a science was entered upon and sketched out once for all... A new light shone upon the first man (Thales, or whatever may have been his name) who demonstrated the properties of the isosceles triangle; for he found that he ought not to investigate that which he saw in the figure or even the mere conception of the same, and learn its properties from this, but that he ought to produce the figure by virtue of that which he himself had thought into it a priori in accordance with conceptions and had represented (by means of a construction), and that in order to know something with certainty a priori he must not attribute to the figure any property other than that which necessarily follows from that which he has himself introduced into the figure, in accordance with his conception."[12] [12] B. x-xii, M. xxvi. Here Kant's point is as follows. Geometry remained barren so long as men confined themselves either to the empirical study of individual figures, of which the properties were to be discovered by observation, or to the consideration of the mere conception of various kinds of figure, e. g. of an isosceles triangle. In order to advance, men had in some sense to produce the figure through their own activity, and in the act of constructing it to recognize that certain features were necessitated by those features which they had given to the figure in constructing it. Thus men had to make a triangle by drawing three straight lines so as to enclose a space, and then to recognize that three angles must have been made by the same process. In this way the mind discovered a general rule, which must apply to all cases, because the mind itself had determined the nature of the cases. A property B follows from a nature A; all instances of A must possess the property B,